Have you ever tried to fly a remote control airplane or helicopter? If you steer too sharply one way, your plane will crash into the ground. And if you go too far in the opposite direction, the plane will nose directly upward, making it difficult to control.

For people with diabetes, controlling blood sugar levels (or blood glucose levels) is kind of like piloting that plane. To stay in the air and have the most fun, you have to keep blood sugar levels steady. Having a blood sugar level that's too high can make you feel lousy, and having it often can be unhealthy.

What Is High Blood Sugar?

The blood glucose level is the amount of glucose in the blood. Glucose is a sugar that comes from the foods we eat, and it's also formed and stored inside the body. It's the main source of energy for the cells of our body, and it's carried to each cell through the bloodstream.

Hyperglycemia (pronounced: hi-per-gly-SEE-me-uh) is the medical word for high blood sugar levels. High blood sugar levels happen when the body either can't make insulin (type 1 diabetes) or can't respond to insulin properly (type 2 diabetes). The body needs insulin so glucose in the blood can enter the cells of the body where it can be used for energy. In people who have developed diabetes, glucose builds up in the blood, resulting in hyperglycemia.

Having too much sugar in the blood for long periods of time can cause serious health problems if it's not treated. Hyperglycemia can damage the vessels that supply blood to vital organs, which can increase the risk of heart disease and stroke, kidney disease, vision problems, and nerve problems in people with diabetes. These problems don't usually show up in kids or teens with diabetes who have had the disease for only a few years. However, these health problems can occur in adulthood in some people with diabetes, particularly if they haven't managed or controlled their diabetes properly.

Causes of High Blood Sugar Levels

Managing diabetes is like a three-way balancing act because you have to watch:

the medications you take (insulin or pills)

the food that you eat

the amount of exercise you get

All three need to be balanced. If any one of these is off, blood sugar levels can be, too. In general, higher than normal blood glucose levels can be caused by:

not taking your diabetes medicine when you're supposed to or not taking the right amounts

not following the meal plan (like eating too much on a special occasion without adjusting your diabetes medicines)

not getting enough exercise

having an illness, like the flu, or stress

taking other kinds of medicines that affect how your diabetes medicines work

A single high blood sugar reading usually isn't cause for alarm — it happens to everyone with diabetes from time to time. However, if you're having high blood sugar levels a lot, let your parents and your diabetes health care team know. Insulin or meal plans may need adjusting, or you may have an equipment issue, like an insulin pump that isn't working properly. Whatever the case, make sure you get help so you can get your blood sugar levels back under control.

Signs and Symptoms

The signs of high blood sugar levels include:

Peeing a lot: The kidneys respond to high levels of glucose in the blood by flushing out the extra glucose in urine. People with high blood sugar need to urinate more often and in larger amounts.

Drinking a lot: Someone losing so much fluid from peeing that often can get very thirsty.

Losing weight even though your appetite has stayed the same: If there isn't enough insulin to help the body use glucose, the body breaks down muscle and stored fat instead in an attempt to provide fuel to hungry cells.

Feeling tired: Because the body can't use glucose for energy properly, a person may feel unusually tired.

Treating High Blood Sugar Levels

Treating high blood sugar levels involves fixing what caused them in the first place. Your diabetes health care team will give you specific advice on how to keep your blood sugar levels in a healthy range, but here are some ways to manage the common causes of high blood sugar levels:

Reason for High Blood Sugar Level

What to Do

Not getting enough insulin or other diabetes medication

Make sure that you take the proper type of insulin and the correct dose at the right time.

Check that insulin is not expired.

Make sure that all equipment (pumps, meters, etc.) is working properly.

What Is Diabetic Ketoacidosis (DKA)?

When the body doesn't have enough insulin, glucose stays in the blood and can't get into the body's cells to be used for energy. This can happen, for example, when someone skips doses of insulin or when the need for insulin suddenly increases (like when a person is sick with the flu) and the doses are not adjusted.

When the body can't use glucose for fuel, it starts to use fat. When this happens, chemicals called ketones are released into the blood. Some of these ketones, like extra glucose, pass out of the body through the urine.

High levels of ketones in the blood can be a problem because they cause the blood to become acidic. Too much acid in the blood throws off the body's chemical balance and causes the symptoms listed below. In people with diabetes, this problem is called diabetic ketoacidosis (pronounced: kee-toe-as-ih-DOE-siss), or DKA. DKA is a very serious condition that can lead to coma or death if it's not treated. The good news, though, is that it's preventable and can be treated so very few teens actually die from it.

DKA occurs more often in people with type 1 diabetes, but can sometimes also happen to those with type 2 diabetes.

Signs and Symptoms of DKA

The symptoms of DKA usually don't develop all at once — they usually come on slowly over several hours. People who have DKA may:

feel really tired

feel really thirsty or pee way more than usual

have a dry mouth and signs of dehydration

The symptoms above are caused by the high blood sugar levels that usually occur before someone develops DKA. If the person doesn't get treatment, these symptoms of DKA can occur:

abdominal pain

nausea and/or vomiting

fruity breath odor

rapid, deep breathing

confusion

unconsciousness ("diabetic coma")

Checking for DKA

How do you know if you have DKA? Because the signs and symptoms of DKA can seem like the flu, it's important to check blood sugar levels and urine (or blood) ketones when you're sick or if you think you're having symptoms of DKA.

Because high levels of ketones appear in the urine (as well as the blood), ketones can be checked at home by testing a sample of your urine. If the urine test for ketones is negative, it usually means your symptoms are not due to DKA. Follow your diabetes management plan about when to check your urine for ketones and what to do if the test is positive. In some cases, your diabetes management team may also have you use special blood test strips to check ketone levels in your blood, too.

Treating DKA

DKA is very serious, but it can be treated if you go to the doctor or hospital right away. To feel better, a person with DKA needs to get insulin and fluids through a tube that goes into a vein in the body (an IV). Let your parents or someone on your diabetes health care team know if you have any of these symptoms or are sick and don't know what to do to take care of your diabetes.

Also, you should always wear a medical identification bracelet or necklace that says you have diabetes. Then, if you are not feeling well, whoever's helping you — even if the person doesn't know you — will know to call for medical help. Medical identification also can also include your doctor's phone number or a parent's phone number.

Avoiding High Blood Sugar and DKA

No matter how well they take care of themselves, people with diabetes will sometimes have high blood sugar levels. But the best way to avoid problems is to keep your blood sugar levels as close to your desired range as possible, which means following your diabetes management plan. Checking your blood sugar levels several times a day will let you know when your blood sugar level is high. Then you can treat it and help prevent DKA from happening.

High blood sugar levels don't always cause symptoms, and a person who isn't testing regularly might be having blood sugar levels high enough to damage the body without even realizing it. Doctors may use the HbA1c test to find out if someone has been having high blood sugar levels over time, even if the person has not had obvious symptoms.

Here are some additional tips for avoiding high blood sugar levels and preventing DKA: